Kiln for making blocks



June 14, 1966 c. J. GULDE ETAL 3,255,866

I KILN FOR MAKING BLOCKS Original Filed Feb. 13, 1961 5 Sheets-Sheet 1 INVENTORS Fl 2 C.J.GULDE8 A.B. HOLMES ATTORNEY June 14, 1966 c. J. GULDE ETAL 3,255,366

KILN FOR MAKING BLOCKS Original Filed Feb. 13. 1961 5 Sheets-Sheet 2 FIGS o. E if 100 l l I l I 2 3 4 5 6 TIME (HOURS) F l G. 4 ,NVENTORS C.J.GULDE a A. B. HOLMES ATTORN EY June 14, 1966 c, J, GULDE ETAL 3,255,866

KILN FOR MAKING BLOCKS Original Filed Feb. 13, 1961 5 Sheets-Sheet 5 INVFJVTORS C. J. GULDE a A. B. HOLIMES Ii WM ATTORN EY United States Patent 4 Claims. (Cl. 198-154) I This application is a divisional application of our application Serial No. 88,701, filed December 13, 1961, now abandoned. This invention relates to the art of making concrete blocks. More particularly, this invention relates to an improved apparatus for handling green blocks produced by conventional block making machines.

The current art of making concrete blocks is described generally in US. Patents 2,106,329; 2,275,676; 2,366,780; and 2,353,492. Such machines produce three blocks at a time, each such block usually having dimensions of about 7 /8" x 7% x 15%. These machines produce about 1,000 greenblocks per hour in the large sizes, 500 to 800 blocks per hour on medium sized machines, and 200 to 500 on the smaller machines.

conventionally, the production of such molding machines is cured at 180 F. for a substantial time, usually 24 hours, before transport to a high-pressure kiln 6 to feet in diameter. There is a total of between 8 to 18 /2 hours required for the curing. This period is usually arranged to approximate 16 hours so as to be accomplised within two standard eight-hour shifts. Such an arrangement provides a large drain on the boiler or other mechanism used to heat the blocks. Additionally, a large capacity heater is required and the control of the treatment leaves much to be desired, as a capacity of the heating mechanism is, for economic reasons, kept at the minimum requisite for the heat demand thereon. Further still, this conventional treatment requires that all the blocks receive the same treatment, regardless of their shape and composition. There is also a long hold up time in the curing system; this allows only a limited use of the 24 hour capacity of the block making machine associated in combination with this curing system.

It is, accordingly one object of this invention to provide a process that requires less heating capacity for a given output of finished blocks than has heretofore been available. Another object of this invention is to provide a process that requires less curing time for a given block making capacity in a plant.

It is a further object of this invention to provide a process freer of heat demand surges than has been heretofore available.

Yet another object of this invention is to provide an improved, substantially continuous process of block making whereby many small heat capacity kiln units may be operated with a substantially uniform overall heat demand to provide an economical, as well as rapid and controllable, method of curing blocks.

For economy of operation of block molding machines used in a competitive commercial manner, it is desirable to release the molds as early as possible i.e., as soon as the produce will stand handling without undue breakage, to realize the full mechanical capacity of the automatic molding machines above-mentioned.

Conventional methods of filling these molds for the above-mentioned types of machine are known and do not form a part of this invention per se.

According to this invention, advantage is taken of the fact that in jarring machines, the concrete cannot contain enough water to produce the strongest final product, for, if sufficient water is added to the molding machine mix to produce a mixture with a-optimum proportion of water for the final product, in view of the cement content of the composition, the product of the molding machine would slump out of shape when removed from the mold. Concrete that is placed in situ requires a greater degree of workability in order to permit satisfactory consolidation than is required in concrete block mixes where heavy vibration and pressure given by the block machine produces the desired compaction.

For further understanding of this invention and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings of the preferred embodiment of this invention.

FIGURE 1 is a diagrammatic generalized plan view of an equipment arrangement in a block-making plant operated according to the process of this invention;

FIGURE 2 is a plan view of another system using the process of this invention;

FIGURE 3 is an enlarged composite diagrammatic view of the transfer feed and discharge mechanism for the kilns, the top half of this figure is taken along arrow 3 of FIGURE 1, the bottom half is taken along arrow 3 of FIGURE 1, to show the relative locations of the components thereof;

FIGURE 4 illustrates the time-temperature relations in one of the kilns according to one embodiment of the process of this invention;

FIGURE 5 is an enlarged longitudinal sectional view along line 5'5" of FIGURE 1 showing the transfer feed and discharge mechanism and support therefor;

FIGURE 6 is a transverse sectional view along the line 6-6" of FIGURE 5;

FIGURE 7 illustrates the time sequenc of heat application and heat demand in a system as in FIGURE 1',

FIGURE 8 illustrates an overall view, partly broken away of an alternative embodiment of kiln within the scope of this invention;

FIGURE 9 is an enlarged cross-section view along section 9'-9 of FIGURE 8; and

FIGURE 10 is a lower longitudinal view, partly in section and partly broken away and partly along section shown by 10'10" of FIGURE 9.

Generally, this invention comprises a process of making and curing concrete blocks and apparatus therefor. This provides excellent control as well as economy in the phase of bringing the green concrete blocks up to what is usually referred to as their holding temperature; this control provides for great uniformity in treatment and in quality of product.

More specifically, according to the process of this invention green concrete blocks are consecutively loaded into each of a series of kilns. A similar program of loading, curing and unloading is applied to each kiln in the series so that while one portion of the output of the process is being treated at one stage of the process in one of the kilns, other portions of the output are simultaneously in other stages of the process.

According to one embodiment of this invention, a conventional block making machine 11, described generally in US. Patent 2,366,780 and repetitively producingthree green blocks, as 12, 13, and 14, at a time in a 20-second cycle, is used. This machine places such blocks on a steel pallet 16 /2 x 26" x 18 /2" in size). A fresh pallet, as 18, is moved into position to receive the blocks during the interval between discharge of the blocks from the machine. Each thus loaded pallet, as 19, passes from the machine at 17A on to a conveyor distribution system indicated generally as 20.

These loaded pallets are passed along a straight chain link power conveyor distribution trunk 21. Therefrom, a mobile entrance power transfer feed mechanism, 22,

9 passes the loaded pallets over a removable bridge portion, 23, thereof into a first kiln 25. This kiln is one of a series of many similar kilns, below described.

On completion of the charging of that one kiln, 25, the bridge portion 23 is moved to the position, 26, shown in dotted lines in FIGURE 3, and the entrance kiln door 27 is closed while the power transfer feed mechanism, 22, is moved to and temporarily fixed at position 29. Thereupon the palleted blocks from the block machine are conveyed to the feed transfer mechanism 22 at position 29, and therefrom, over bridge portion 23 into the next kiln 32. The transfer mechanism 22 similarly subsequently passes to position 33 to charge third kiln 35 over its bridge portion 23, then moves to position 36 to charge fourth kiln 37, and so forth. On each kiln, as 25, the kiln conveyor mechanism 411, and discharge conveyor, 42, discharge the contents of each kiln from the same end of the kiln as that at which it is fed, i.e., at the inlet end, prior to charging of each such kiln, as above described.

For such discharge, the kiln inlet door, 27, is opened after the mobile chain drive discharge conveyor, 42, is moved into position to receive the pallets loaded with cured blocks. Such pallets and blocks are moved by the kiln chain drive conveyor mechanism 40 to the dischage bridge conveyor 41, which omnilex belt bridge is hingedly attached to the mobile unit 42 and the top of which bridge unit is coplanar with the top surface of the body of conveyor 42 and with the top level of the kiln conveyor, as 40 and 40', in the kilns, as 25 and 32, respectively.

These loaded pallets of cured blocks are then transported on the lower discharge'portion, 79, of the chain drive conveyor 21 to a stripper station 45 whereat fingers 46 remove the pallets with cured blocks. Empty pallets, as 47 and 47', are returned via roller conveyors 48 and 49 to the point '18 from which fresh pallets are fed to the molding machine, 11, and finished blocks are sent to storage 50 from station 45.

In another embodiment of apparatus according to this invention, each kiln, as 25, is provided for discharge with a discharge device 24 similar in structure to transfer mechanism 22, such mechanism 22 being then run backwardsto serve as a discharging device, 24; such device is then used at a kiln exit door 51, located at the discharge end of the kiln, distant from the entrance door 27', and feeds the products of each kiln to a separate collector conveyor 52 identical in construction to the top portion of conveyor 21 above described, and said conveyor 52 moves from one kiln to the next as above described for conveyors 22 and 42.

The main distribution conveyor, 21, comprises a frame, 70, supporting an upper set of channels, 71 and 72, and a lower set of channels 73 and 75. These channels support the link belt chains 76 and 78 that provide locomotion for the pallets. The upper level 77 provides for feed to the kilns from the block making machine. The lower discharge level 79 transports the pallets loaded with the cured blocks in the opposite direction. A conventional sprocket drive is provided at the end of the frame 70 for chains 76 and 78, which are continuous chains.

The power feed transfer conveyor, 22, is mobily supported on a pair of rails, 86, between conveyor, 21, and the line of kilns. These rails run for the length of the area covered by the kilns and a little bit further to provide for the repair, dismantling, etc. therefor. The load of the transfer mechanism is also borne in part, as at 85, by the frame 70. The sprockets 81' and 82 driving the chains, 87 and 88, of the conveyor, 22, are driven by an electrical motor 83 attached to and movable with the conveyor 2-2.

Sprockets 81 and 82'- of conveyor 22 are of unequal diameter so that notwithstanding that both sprockets are attached to the same drive shaft and inner chain 87 moves more slowly than outer chain 88, these chains cooperate to maintain the orientation of the axis of the pallets thereon near conveyor 77 asymptotic with the direction of the flow along conveyor 77 and so avoid sudden movement of these blocks in the green condition, and so deliver said blocks smoothly to the kiln. Chains 81 and 82 are continuous.

The terminal section 90 of the discharge conveyor'42 is rotatably and detachably attached to the main portion thereof 91; it provides a passage of the pallets with cured blocks asymptotic to conveyor 79 and so provides a smooth gravity transfer of the load of cured blocks from discharge conveyor 42 to lower level 79 of conveyor 21. Such discharge conveyor is mobile; it runs on its own pair of rails 92; the body 93 of this conveyor is also rotatable about a vertical axis on a horizontal plane on its support 94 so that the discharge conveyor 42 may pass below the support 95 of the feed conveyor 22 and Well as to facilitate the positioning of the terminal section of the discharge conveyor 42 asymptotic to the line of conveyor 79 between the vertical members of the frame, 70.

Each kiln as 25, 32, 37, etc., has a l30-foot length and a 30 inch internal diameter. A pair of endless drive chains, 60 and 61, are provided in each kiln. Each such chain operates in a channel therefor, 62 and 63, respectively. The channels are removably supported in the kiln by a frame, 65, therefor. The chains are driven by sprocket drive, as 66, at the end of such kiln. The chain links are provided with lugs 67, spaced 19 inches apart which positively guide the loaded pallets as 19' through the kiln and position the pallets positively therein. Antifriction bearings, 69, assist in supporting the weight of the pallets. The kiln is thus arranged to receive 15 minutes of the output of the block machine, 11, when such machine operates at the rate of 540 blocks per hour. The apparatus thus provides for the loading of the entire series of kilns to approach a continuous process by use of a series of continual 45-minute loading increments.

Following the completion of the loading of any one kiln, the bridge 23 is withdrawn from the entrance to the kiln, the entrance door 27 is closed, and the curing cycle below described is applied to the contents of the kiln.

Afterthe blocks are placed in the kiln as above described, heat is applied to such blocks by use of steam, controlled by conventional plumbing. Using, first, a preset time of only /2 hour and venting to remove air, followed by a build-up time of 1 /2 hours with 150 p.s.i.g. saturated steam and, thereafter, a holding time of 3 hours at 365 F., for a total cycle time of 5% hours and a formula of 200 pounds cement (ASTM Type 1),

pounds silica, 2,300 pounds sand, 2,300 pounds of rock,

and 33 gallons water, concrete block of 1415 p.s.i. strength (ASTM Test No. C9042) result from the process as above described.

FIGURE 7 illustrates the relations of the several steps in the cycle for one kiln and the relation of the corresponding and similar steps in the other kilns when, e.g., 22 kilns are used in the process above described. As shown in the lower part of FIGURE 7, it will be noted there is a relatively gradual increase in the heat demand until a stable level is reached (as shown by plateau 99, at which time when one kiln operation is closed, another kiln is brought into operation. A relatively steady state is then obtained with the blocks being discharged from the kilns and being fed to other kilns at a constant rate over any 15-minute period. Using this procedure, a boiler, as 30 in FIGURE 1, of only 75 boiler horsepower is required while conventional processes using conventional equipment require a boiler with a rating of 225 boiler horsepower to effect the production accomplished by the process above described.

The several kilns as 25, 32, 35, 37, etc., are operated in a sequence as above described by standard programmers or automatic instruments such as 96, 97, and 98 for each of kilns 25, 32, and 35, respectively, in FIG- URE l and, also, one for each of the other kilns, as 37. The programmers control valves as 96', 97', and 98',

respectively, for kilns 25, 32, and for the headers for each of these kilns, as 89 in kiln 25; such valves control the passage of air, low pressure steam, high pressure steam, and for venting via appropriate piping therefor, as pipes 100, 101, 102, and 103, respectively. The feature of using only a single rack of green concrete blocks to be cured in each kiln permits a very close control and treatment of all the contents of each kiln. Thus, FIG- URE 7 illustrates the time sequence of heat application and overall heat demand in a system as above described for FIGURE 1 using, for each kiln in the series, a program of, first, one-half hour preset, then /2 hour of one p.s.i.g. saturated steam, followed by /4 hour build-up to 365 F., and then a 3 hour holding a blow down of hour (for a total cycle time of 5 /2 hours) with the above-mentioned concrete mix for a concrete block, and produces blocks testing at 1425'to 1450 p.s.i. (tested as above noted). The illustrated method of passing steam from the header to the kilns (illustrated in the drawings) wherein relatively even distribution of the heating medium is obtained by spacing the inlet valves at six feet longitudinal intervals along the length of the kilns (6 feet longitudinal distance between valves), with alternative valves entering into the interior of the kiln at the top and at the bottom of the kiln as shown in FIGURE 6, is a preferred embodiment of this invention but the invention is not limited thereto.

It will thus be seen that, according to this invention, there is provided a flow pattern utilizing a plurality of small volume kilns, and that the flow of the material through these kilns is such that while one portion of the plant output is being treated at one stage of the process in one of the kilns other portions of the output are simultaneously in other stages of process. This treatment thus allows continuous plant operations at substantially steady heat demand for any number of hours of 6 to 24 hours per day as above shown. The material arrangement also permits gravity flow of the major portion of the feed along the conveyor distribution system with positively driven conveyors 21, 22, 40, 42, 48 (and 52 if present) providing for direct control of the position of the blocks being treated. Only a minor portion of the blocks are lifted up and down at any one instant. This material flow arrangement allows delicate control treatment of any particular batch as well as variation in treatment of each of the rather small increments of capacity provided for by the apparatus of this invention. By the use of this apparatus the capital cost on the boiler, insulation on transmission line, etc., also, is dramatically reduced. Additionally, there is a much more efficient use of the plant operation time and labor.

In an alternative form of this invention, a vertical kiln as in FIGURE 8 may be used in place of horizontal kilns such as 25, etc., in the arrangement of FIGURES 1 and 2. Such vertical kilns are fed as above-described for the horizontal kilns. In the vertical kiln the interior volume is more efficiently used than in the arrangement shown in FIGURES 3, 5, and 6 because of the denser spacing of the blocks permissible by the vertical arrangement. In this vertical kiln arrangement the feed and discharge devices used would be those shown in FIG- URES 1, 3, and 5. The loaded pallets, as 19, carrying blocks as 106, 106' and 106", passing into entrance 107 past the open kiln door 108 are supported on lateral lugs as 109, 110, 111, and 112 and are lifted thereby. These lugs are supported by chains as 113, 115, 116, and 117, respectively. Chain 113 is located in a relatively central- 1y located channel 119 on its upward travel and in an opposite peripheral channel 121 when traveling downward; chain is also located in a relatively central channel 123 while traveling upward and in a peripheral channel 124 when traveling downward; chain 116 is similarly located in channel 125 when traveling upwards and in channel 126 when traveling downward; chain 117 is simperiod followed by ilarly in channel 127 when traveling upward and in channel 129 when traveling downward. The arrangement provides that the lugs will be urged by their channels to' be close to the pallets supported thereby during the upward travel of the chain, while the lugs are peripherally located and do not contact or interfere with downward motion of the pallets. A motor 130 serves to drive sprocket wheels as 131 and 132 through their shafts 133 and 134, respectively. Piping, valves, headers, inlets, control and programming are the same as above described for the embodiment of FIGURES 1-4. Internal diameter is 34 inches; overall height is 75 feet for such kilns.

The temperature and pressure as above described p.s.i.g., 365 F.) are illustrative of this invention rather than limiting. The invention encompasses the use of pressures up to 300 p.s.i.g, which pressure result in a reduction, to of about /2, of the time of cure above-disclosed for satisfactory (over 1,000 p.s.i. tests) results. A saturated steam pressure of about 225 p.s.i.g. (temperature of 392 F.) has been found most desirable for curing, present economic factors considered. It is, thus, clearly within the scope of this invention to operate on a 4-hour cycle as well as on the 5-hour cycle of FIGURE 7 above discussed as an illustrative example. Further, the particular time sequence above disclosed is one chosen to match the particular output of the above described molding machine (11); when higher output molding machines are used more kilns of the given size or same number of kilns of a larger size are used. However, when more kilns are used or available so that more than one kiln is turned on in any 15-minute periodor other time increment between when cycles for successive kilns in a series beginsthe use of such additional kilns, as 23 to 25 shown in FIGURE 7, according to the process of this invention only results-for a cycle period as shown in FIGURE 7-in a somewhat higher plateau (137) than at 199 (when one kiln turns on as another turns off) following a gradual increase in the heat demand/time slope indicated by 138 in FIGURE 7. The heat demand/ time slope 138 is steeper than corresponding slope 139 because of the greater rate of additional heat demand put on the system; this still is, overall, only a gradual rather than a sudden rate of increase. The size of the kilns may also be increased in pursuance of the above described practice. However, as shown in FIGURE 7, the process of this invention permits a gradual increase in block curing capacity with the same degree of control over each phase of the heating cycle for each batch treated with only a corresponding gradual increase in heat capacity.

In the sequence above described of addition of the heat to the kiln contents the air is first vented prior to the addition of steam. Also, water may be added to the vessel when loading it in order to equalize the initial temperatures for successive cycles in the same: kiln. Water may also be added for any period of time at which the high pressure steam is turned on in order to provide a uniform, saturated, atmosphere for similar repetitive treatment of all material in the same kiln.

'Another arrangement embodying the process of this invention is illustrated in FIGURE 2. In. this embodiment several kilns, as 141-150, of either the vertical type of FIGURE 8 or the horizontal type of FIGURE 1 are arranged to surround a centrally located block machine, 153; a conveyor 154 has a two-level structure as in conveyor 21 but is arranged in circular continuous form. The feed and discharge conveyors 22 and 42 above-described would be used in this arrangement as above described for the arrangement of FIGURE 1. Cured blocks would be discharged to storage at 155 and pallets as 140 gathered at 156 for continual feeding to the block making machine 153 in the same manner as above described for machine 11.

The time/heat demand requirements would generally be the same as in FIGURE 7 for the arrangement of FIGURE 1 as the only difference between the arrangement of FIGURE 1 (using the kiln of FIGURE 8) and FIGURE 2 using the same type size and capacity of kiln is that the kiln feed distribution trunk 21 in FIGURE 1 is rectilinear, while that of FIGURE 2, item 154, is a closed loop. The number of kilns 141450 about the loop conveyor 154 may be increased as desired, as may those about conveyor 21, in order to provide the relatively steady heat demandas at plateau 99 or 137 of FIGURE 7during that steady state and relatively gradual increase of heat demandas at slope 139-during the initial period of the process for the series of kilns so used.

Though we have shown and described certain embodi ments of our invention, we do not wish to be limited thereto, but desire to include in the scope of our invention the constructions, combinations and arrangements substantially as set forth in the appended claims.

We claim:

1. A kiln apparatus for use in the process of treating green concrete blocks, said apparatus comprising an elongated vertical cylindrical kiln chamber circular in horizontal cross section, a plurality of pallets, said pallets each having the same size, said pallets each having a major dimension substantially the same as but slightly less than the interior diameter of said kiln and a minor dimension substantially less than the internal diameter of said kiln, whereby each said pallet is movable in a horizontal position upward and downward in said kiln through a vertically extending zone with a transverse cross section of the same horizontal cross section as said pallets, said concrete blocks being disposed in like groups in a single layer on each of said pallets, and a first set of movable pallet supports comprising a first plurality of vertically extending endless chains each supported to travel in an upward vertical path within said chamber, the said chains each having a plurality of vertically equispaced horizontally extending lugs on one side thereof, said lugs on each of said chains being at the same vertical level and each of the said lugs at one vertical level of said first plurality of chains extending under and supporting one side of one of said pallets on the upward movement of said first plurality of said chains, and a second set of pallet supports comprising a second plurality of vertically extending endless chains in said chamber, each of said chains being movably supported to travel in an upward vertical path within said chamber, each of said chains having a plurality of vertically equispaced horizontally extending lugs, said lugs on each of said second plurality of chains being at the same vertical level and each of the said lugs at one vertical level of said second plurality of chains extending under and supporting the other side of said one of said pallets during the upward movement of said second plurality of chains, guide means in contact with and constraining each of said plurality of chains to travel upwardly in substantially only one plane, and to maintain said relationship of said lugs and said pallets, the guide means for one of said plurality of chains supporting a first lug on one side of one of said pallets comprises a first sprocket wheel and the guide means for the chain supporting a lug on the other side of said pallet opposite said first lug of said first plurality of chains is a second sprocket wheel and the plane of rotation of said second sprocket wheel is at an angle to the plane of rotation of said first sprocket wheel, and means to move each of said chains carrying lugs beneath said pallets upwardly and downwardly, said means to move said chains being operatively connected to said chains, said pallets being rectangular, said major dimension being a major diagonal dimension thereacross and said minor dimension being a minor diagonal thereacross.

2. A kiln apparatus for use in the process of treating green concrete blocks, said apparatus comprising an elongated vertical cylindrical kiln chamber circular in horizontal cross section, a plurality of pallets, said pallets each having the same size, said pallets each having a major dimension substantially the same as but slightly less than the interior diameter of said kiln and a minor dimension substantially less than the internal diameter of said kiln, whereby each said pallet is movable in a horizontal position upward and downward in said kiln through a vertically extending zone with a transverse cross section of the same horizontal cross section as said pallets, said concrete blocks being disposed in like groups in a single layer on each of said pallets, and a first set of movable pallet supports comprising a first plurality of vertically extending endless chains each. supported to travel in an upward vertical path within said chamber, the said chains each having a plurality of vertically equispaced horizontally extending lugs on one side thereof, said lugs on each of said chains being at the same vertical level and each of the said lugs at one vertical level of said first plurality of chains extending under and supporting one side of one of said pallets on the upward movement of said first plurality of said chains, and a second set of pallet supports comprising a second plurality of vertically extending endless chains in said chamber, each of said chains being movably supported to travel in an upward vertical path within said chamber, each of said chains having a plurality of vertically equispaced horizontally extending lugs, said lugs on each of said second plurality of chains being at the same vertical level and each of the said lugs at one vertical level of said second plurality of chains extending under and supporting the other side of said one of said pallets during the upward movement of said second plurality of chains, guide means in contact with and constraining each of said plurality of chains to travel upwardly in substantially only one plane, and to maintain said relationship of said lugs and said pallets, the guide means for one of said plurality of chains supporting a first lug on one side of one of said pallets comprises a first sprocket wheel and the guide means for the chain supporting a lug on the other side of said pallet opposite said first lug of said first plurality of chains is a second sprocket wheel and the plane of rotation of said second sprocket wheel is at an angle to the plane of rotation of said first sprocket wheel, and means to move each of said chains carrying lugs beneath said pallets upwardly and downwardly, said means to move said chains being operatively connected to said chains, said pallets being rectangular, said major dimension being a major diagonal dimension thereacross and said minor-dimension being a minor diagonal thereacross and wherein each of said pallets is supported in a horizontal position by a plurality of said lugs, each of said lugs being on a different chain, each of said chains travelling in a vertical direction at the same speed as each of the other chains.

3. A kiln apparatus for use in the process of treating green concrete blocks, said apparatus comprising an elongated vertical cylindrical kiln chamber circular in horizontal cross section, a plurality of pallets, said pallets each having the same size, said pallets each having a major dimension substantially the same as but slightly less than the interior diameter of said kiln and a minor dimension substantially less than the internal diameter of said kiln, whereby each said pallet is movable in a horizontal position upward and downward in said through a vertically extending zone with a transverse cross section of the same horizontal cross section as said pallets, said concrete blocks being disposed in like groups in a single layer on each of said pallets, and a first set of movable pallet supports comprising a first plurality of vertically extending endless chains each supported to travel in an upward vertical path within said chamber, the said chains eaoh having a plurality of vertically equispaced horizontally extending lugs on one side thereof, said lugs on each of said chains being at the same vertical level and each of the said lugs at one vertical level of said first plurality of chains extending under and supporting one side of one of said pallets on the upward movement of said first plurality of said chains, and a second set of pallet supports comprising a second plurality of vertically extending endless chains in said chamber, each of said chains being movably supported to travel in an upward vertical path within said chamber, each or said chains having a plurality of verti cal-1y equispaced horizontally extending lugs, said lugs on each of said second plurality of chains being at the same vertical level and each of the said lugs at one vertical level of said second plurality of chains extending under and supporting the other side of said one of said pallets during the upward movement of said second plurality of chains, guide means in contact with and constraining each of said plurality of chains to travel upwardly in substantially only one plane, and to maintain said relationship of said lugs and said pallets, the guide means for one of said plurality of chains supporting a first lug on one side of one of said pallets comprises a first sprocket wheel and the guide means for the chain supporting a lug on the other side of said pallet opposite said first lug of said first plurality of chains is a second sprocket wheel and the plane of rotation of said second sprocket wheel is at an angle to the plane of rotation of said first sprocket wheel, and means to move each of said chains carrying lugs beneath said pallets upwardly and downwardly, said means to move said chains being operatively connected to said chains, said pallets being rectangular, said major dimension being a major diagonal dimension thereacross and said minor dimension being a minor diagonal thereac-ross and wherein said sprocket means each extends from a position in said chamber on one side of the longitudinal axis of said pallet adjacent one edge of said vertically extending zone of movement of said pallets to a position on the other side of said longitudinal axis in said chamber, said other position in said chamber being at a greater radial distance from the geometrical center of said chamber than said one position.

4. A kiln apparatus for use in the process of treating green concrete blocks, said apparatus comprising an elongated vertical cylindrical kiln chamber circular in horizontal cross section, a plurality of pallets, said pallets each having the same size, said pallets each having a major dimension substantially the same as but slightly less than the interior diameter of said kiln and a minor dimension substantially less than the internal diameter of said kiln, whereby each said pal-let is movable in a horizontal position upward and downward in said kiln through a vertically extending zone with a transverse cross section of the same horizontal cross section as said pallets, said concrete blocks being disposed in like groups in a single layer on each of said pallets, and a first set of movable pallet supports comprising a first plurality of vertically extending endless chains each supported to travel in an upward vertical path within said chamber, the said chains each having a plurality of vertically equispaced horizontally extending lugs on one side thereof, said lugs on each of said chains being at the same vertical level and each of the said lugs at one vertical level of said first plurality of chains extending under and supporting one side of one of said pallets on the upward movement of said first plurality of said chains, and a second set of pallet supports comprising a second plurality of vertically extending endless chains in said chamber, each of said chains being movably supported to travel in an upward vertical path within said chamber, each of said chains having a plurality of vertically equispaced horizontally extending lugs, said lugs on each of said second plurality of chains being at the same vertical level and each of the said lugs at one vertical level of said second plurality of chains extending under and supporting the other side of said one of said pal-lets during the upward movement of said second plurality of chains, guide means in contact with and constraining each of said plurality of chains to travel upwardly in substantially only one plane, and to maintain said relationship of said lugs and said pallets, the guide means for one of said plurality of chains supporting a first lug on one side of one of said pallets comprises a first sprocket wheel and the guide means for the chain sup-porting a lug on the other side of said pallet opposite said first lug of said first plurality of chains is a second sprocket wheel and the plane of rotation of said second sprocket wheel is at an angle to the plane of rotation of said first sprocket wheel, and means to move each of said chains carrying lugs beneath said pallets upwardly and downwardly, said means to move said chains being operatively connected to said chains, said pallets being rectangular, said major dimension being a major diagonal dimension thereacross and said minor dimension being a minor diagonal thereacross and wherein said sprocket means each extend from a position in said chamber on one side of the longitudinal axis of said pallet adjacent one edge of said vertically extending zone of movement of said pallets to a position on the other side of said longitudinal axis in said chamber, said other position in said chamber being at a greater radial distance from the geometrical center of said chamber than said one position and wherein each said pallet is rectangular in shape, one side being longer than the other, and the said chains and the guide means therefor are located between the longer sides of the pallets and the interior wall of said vertical cylindrical chamber.

References Cited by the Examiner UNITED STATES PATENTS Re. 14,111 4/1916 Hilke 198-154 1,504,886 8/1924 Gibbs 198163 2,168,391 8/1939 Bemis 107-57 2,251,197 7/1941 Nestmann 198-85 2,512,356 6/1950 Massiello 198-138 3,034,666 5/1962 ONeill 21416.12

HUGO O. SCHULZ, Primary Examiner.

MICHAEL V. BRINDISI, SAMUEL F. COLEMAN,

Examiners.

G. A. KAP, EDWARD A, SROKA, Assistant Examiners, 

1. A KILN APPARATUS FOR USE IN THE PROCESS OF TREATING GREEN CONCRETE BLOCKS, SAID APPARATUS COMPRISING AN ELONGATED VERTICAL CYLINDRICAL KILN CHAMBER CIRCULAR IN HORIZONTAL CROSS SECTION, A PLURALITY OF PALLETS, SAID PALLETS EACH HAVING THE SAME SIZE, SAID PALLETS EACH HAVING A MAJOR DIMENSION SUBSTANTIALLY THE SAME AS BUT SLITHTLY LESS THAN THE INTERIOR DIAMETER OF SAID KILN AND A MINOR DIMENSION SUBSTANTIALLY LESS THEN THE INTERNAL DIAMETER OF SAID KILN, WHEREBY EACH SAID PALLET IS MOVABLE IN A HORIZONTAL POSITION UPWARD AND DOWNWARD IN SAID KILN THROUGH A VERTICALLY EXTENDING ZONE WITH A TRANSVERSE CROSS SECTION OF THE SAME HORIZONTAL CROSS SECTION AS SAID PALLETS, SAID CONCRETE BLOCKS BEING DISPOSED IN LIKE GROUPS IN A SINGLE LAYER ON EACH OF SAID PALLETS, AND A FIRST SET OF MOVABLE PALLET SUPPORTS COMPRISING A FIRST PLURALITY OF VERTICALLY EXTENDING ENDLESS CHAINS EACH SUPPORTED TO TRAVEL IN AN UPWARD VERTICAL PATH WITHIN SAID CHAMBER, THE SAID CHAINS EACH HAVING A PLURALITY OF VERTICALLY EQUISPACED HORIZONTALLY EXTENDING LUGS ON ONE SIDE THEREOF, SAID LUGS ON EACH OF SAID CHAINS BEING AT THE SAME VERTICAL LEVEL AND EACH OF THE SAID LUGS AT ONE VERTICAL LEVEL OF SAID FIRST PLURALITY OF CHAINS EXTENDING UNDER AND SUPPORTING ONE SIDE OF ONE OF SAID PALLETS ON THE UPWARD MOVEMENT OF SAID FIRST PLURALITY OF SAID CHAINS, AND A SECOND SET OF PALLET SUPPORTS COMPRISING A SECOND PLURALITY OF VERTICALLY EXTENDING ENDLESS CHAINS IN SAIUD CHAMBER, EACH OF SAID CHAINS BEING MOVABLY SUPPORTED TO TRAVEL IN AN UPWARD VERTICAL PATH WITHIN SAID CHAMBER, EACH OF SAID CHAINS HAVING A PLURALITY OF VERTICALY EQUISPACED HORIZONTALLY EXTENDING LUGS, SAID LUGS ON EACH OF SAID SECOND PLURALITY OF CHAINS BEING AT THE SAME VERTICAL LEVEL AND EACH OF THE SAID LUGS AT ONE VERTICAL LEVEL OF SAID SECOND 